Trip mechanism for welding crucible



23, 1966 G. B. YAEGER TRIP MECHANISM FOR WELDING CRUCIBLE Filed Feb. 21, 1964 I NVENTOR- EORGE E. WMGER M/L 501v SETTLEZ RQ/a ,QrTOR EKS United States Patent 3,267,533 TRIP MECHANISM FOR WELDING CRUCIBLE George B. Yaeger, 8701 Belleville Ave., Belleville, Mich. Filed Feb. 21, 1964, Ser. No. 346,455 Claims. (Cl. 2285) The present invention relates to a trip mechanism for a welding crucible, and more particularly to tripping means for accurately tapping a welding crucible containing molten metal from a point remote from the crucible.

The present invention is particularly applicable for tripping the crucibles utilized in the aluminothermic process for rail welding. In this process, the rails of a railroad track are welded together to form a continuous rail as opposed to the conventional system of constructing a track of individual rail sections. In the a-luminothermic process, a mold is provided around adjacent ends of two rail sections, the adjacent ends being separated by a gap of predetermined size. Molten metal is cast into the mold from a crucible located directly above the mold to join the rail sections together. The crucible is initially charged with granular aluminum and iron oxides. These materials wi-ll chemically react, when heated to an elevated temperature, to form aluminum oxide and pure iron. During the chemical reaction, the material boils vigorously. At the termination of the boiling, the crucible is tapped and the molten metal fills the mold.

A problem has been encountered in properly taping the crucible. The crucible is provide with an opening at the bottom thereof which is sealed with an asbestos disc. A firing pin is in contact with the undersurface of this disc, the firing pin extending outwardly from the bottom of the crucible. T-he asbestos disc may be knocked out of its position by driving the firing pin upwardly into the crucible. 'Conventionally, the firing pin is tripped by a worker standing a short distance away from the crucible. The worker has a tripping rod with which to strike the firing pin. The firing pin must be tripped at the moment the boiling within the crucible ceases. T=he firing pin is tripped by using a brisk and sharp upward stroke. The point at which the firing pin is tripped is important. If the pin is tripped too early, slag will be trapped inside the resultant weld. If the firing pin is tripped too late, the firing pin will become welded within the crucible. If the firing pin is not tripped at the precise moment and if it is not tripped efficiently, a faulty weld will take place. As will be appreciated, the welder must stand close to the crucible during the boiling action so that he can trip the firing pin at the exact moment when the boiling ceases. During the boiling action, molten metal is frequently splashed from the crucible onto the worker, causing the worker to be burned. Under these trying circumstances, the worker is frequently unable to properly strike the firing pin and thus faulty welds are frequently encountered. These problems are overcome by the present invention by the provision of a tripping mechanism which permits the worker to stand a safe distance away from the crucible and yet still be able to accurately trip the crucible at the exact moment when boiling ceases.

It is therefore an object of the present invention to provide a tripping mechanism for a welding crucible, the tripping mechanism permitting the welder to trip the crucible from a remote point.

Another object of the invention is to provide such a tripping mechanism which is readily incorporated into the structure of conventional welding units.

A further object of the invention is to provide a tripping mechanism which has a novel structure for actuating a tripping rod first in an upward tripping motion and then immediately after in a sideward motion to avoid contact with molten metal flowing from the crucible.

3,267,533 Patented August 23, 1966 A still further object of the invention is to provide a bearing for mounting the tripping rod which permits both upward and sideward motion of the tripping rod.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawing:

FIGURE 1 is a view in perspective of one embodiment of the trip mechanism for a welding crucible of the present invention;

FIG. 2 is an end elevational view of the crucible and tripping mechanism with parts broken away for the purpose of clarity FIGURE 3 is an enlarged view in perspective of the upper portion of the spring actuated plunger means utilized in the invention; and

FIGURE 4 is a cross-sectional view taken substantially along the line 44 of FIGURE 1 looking in the direction of the arrows.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to FIGURE 1, it will be noted that a crucible 10 is mounted in a carriage structure 12. The carriage structure 12 has a configuration similar to that of a wheelbarrow. The carriage 12 includes a main frame 14 comprising side rails 16, 18 connected together at their rear ends by end rail 20 and at their front ends by a generally U-shaped member 22. A ring 24 is formed at the apex of the member 22 and receives the conically shaped crucible 10. Extending forwardly from the apex of the member 22 is a support member 26. A downwardly projecting leg 28 is secured to the member 26 adjacent the forwardmost end thereof. A pivotal flanged wheel 30 is provided at the lower end of the leg 28. The wheel 30 is adapted to engage a rail of a railroad track to permit movement of the entire assembly along the track.

A pair of spaced apart handles extend rearwardly from the end rail 20. Extending downwardly from each handle 32, 34 is a ground engaging leg 36, 38. It will thus be appreciated that the main frame 14 and crucible 10 are supported in spaced apart relation from the ground by the three legs 28, 36 and 38.

The structure thus far described is conventional. In operation of this device, the entire assembly is moved along a rail until the point at which the weld is to be made is reached. The crucible 10 is then centered over a mold and charged preparatory to the welding operation. The charge is then ignited and the molten metal is eventually tapped from the crucible to flow into the mold.

The structure for tapping the crucible is illustrated in FIGURE 2. As will be noted, a charge 40 is received within the cavity 42 of the crucible 10. An opening 44 is provided at the lower end of the crucible. The opening 44 is normally plugged by an asbestos disc 46. A firing pin 48 abuts against the undersurface of the disc 46, the shank 50 of the firing pin 48 extending downwardly and exteriorly of the crucible 10. A dowel 52 is provided to maintain the pin 48 in place and to guide the pin when the pin is moved upwardly to displace the disc 46. It will be appreciated that at the proper moment, the pin 48 is driven upwardly to move the disc 46 out of its plugging position and permit the molten metal to flow through the opening 44.

The trip mechanism for driving the pin 48 upwardly to tap the crucible will now be described. The trip mechanism includes an elongated firing rod 54. One end 56 of the rod 54 terminates directly beneath the pin 48. The end 56 is spoon shaped for secure engagement with the lower end of the pin 48.

The rod 54 is pivotally mounted intermediate its ends.

Referring to FIGURES 1 and 4, it will be noted that forming a part of the firing rod 54. The lower socket member 66 is secured to the leg 78 of the cross member 62 as by welding. An opening 82 is provided in the upper leg 84 to receive the members 66, 68. As will be appreciated, the ball 76 is free to pivot in both vertical and horizontal directions within the socket members 66, 68.

Power means comprising spring actuated plunger means 86 are provided adjacent the rearward end of the firing rod 54 to drive the rearward end of the firing rod downwardly with consequent upward motion of the spoonshaped forward end 56 to contact the firing pin 48 and drive this member upwardly to tap the crucible 10. The

plunger mechanism 86 includes a plunger shank 88 having a hand grip 90 at its upper end and a fiat plate member 92 at its lower end for contact with the rod 54. The shank 88 is received and guided in a structure comprising a U-shaped member 94 having a plate 96 across the across the lower end thereof. The U-shaped member 94 has angle brackets 98, 100 at each side thereof, the angle brackets 98, 100 being secured to main frame member 20. Openings are provided in the U-shaped member 94 and plate 96 for passage of the shank 88. A coil spring 102 is received on the shank 88 and is secured at its lower end to the plate 96 and at its upper end to the shank 88.

As will be noted in FIGURE 3, the shank 88 has a slot 104 adjacent the upper end thereof. The shank 88 is locked in an upper tripping position with the spring 102 in an extended position by engagement of the slot 104 with the edge portion adjacent the opening 106. This engagement is accomplished by moving the shank sidewardly after it has been drawn upwardly. As will be appreciated, when the shank is moved sidewardly to disengage the slot 104, as by use of a long pole by a worker at a point remote therefrom, the spring 102 will pull the shank downwardly causing the plate 92 to strike the firing rod 54 thus driving the spoon end 56 upwardly against the firing pin 48. Automatic timing means may be provided to actuate the plunger mechanism if desired.

A U-shaped member 108 is provided adjacent the forward end of the firing rod 54 to hold the rod 54 in place priorto the tapping action and to guide the forward end of the rod 54 in its upward stroke to strike the firing pin 48. The member 108 is fabricated from rod material and comprises legs 110, 112 which extend downwardly from flanges 117, 119 on the main frame rails 16,- 18 and are connected together by cross member 114. The upper ends of legs 110, 112 are threaded and are adjustably secured in place by lock nuts 113, 115. Member 114 has a U-shaped downwardly extending portion 116 at approximately its midpoint. As will be noted, the rod has a generally square enlarged portion 109 for reception in the U-shaped portion 116. An upwardly extending projection 118 is provided at one side of the portion 116 as .an aid in guiding the rod 54 into the A ball and socket means 64 is portion 116., The leg 120 of the portion 116 acts as a guide to direct the end 56 vertically to strike the pin 48 and drive it into the crucible 10. The length of the leg 120 is just sufficient to assure that the pin 48 will be driven into the crucible a distance to displace the disc 46 and free the opening 44.

Once the molten metal begins to fiow from the crucible 10, the end 56 of the rod 54 must be moved out of the way. A pair of coil springs 122, 124 are provided to move the rod 54 sidewardly after the crucible has been tapped. One of the springs 1-22, 124 is provided on either side of the ball and socket structure 64. The springs 122, 124 extend from the rod 54 to the cross member 62 and bias the rod 54 in a clockwise direction as viewed in FIGURE 1 when the rod is engaged in the U-shaped portion 116. After the pin 48 has been driven into the disc 46 to tap the crucible 10 as shown in dotted lines in FIGURE 1, the rod 54 clears the leg 120 and then the springs 122, 124 move the rod sidewardly as shown in dotted lines in FIGURE 2 out of the path of molten stream of metal.

It will be appreciated that the trip mechanism thus described provides a simple and effective method for tapping the crucible 10. The trip mechanism always drives the pin 48 accurately, thus avoiding human error. Additionally, the worker may stand a safe distance away from the crucible 10 and still actuate the plunger mechanism 86 at the proper moment.

Having thus described my invention, I claim:

1. For use in combination with a welding crucible for molten metal, the crucible having a discharge open-ing at the lower end, a firing pin extending downwardly from the opening and drivable upwardly to free the opening for the discharge of molten metal, the crucible being mounted in a frame, a tripping mechanism comprising a firing rod pivotally mounted intermediate its ends, means for positioning the forward end of the rod beneath the firing pin, guide means for directing said forward end upwardly to drive the firing pin upwardly and free said crucible opening, power means for driving the rearward portion of the firing rod downwardly and the forward portion upwardly, and biasing means for pivoting the firing rod sidewardly away from said crucible opening subsequent to driving the firing pin upwardly.

2. For use in combination with a welding crucible for molten metal, the crucible having a discharge opening at the lower end, a firing pin extending downwardly from the opening and drivable upwardly to free the opening for the discharge of molten metal, the crucible being mounted in a frame, a tripping mechanism comprising a firing rod pivotally mounted intermediate its ends, means for positioning the forward end of the rod beneath the firing pin, guide means for directing said forward end upwardly to drive the firing pin upwardly and free said crucible opening, spring actuated power means for driving the rearward portion of the firing rod downwardly and the forward portion upwardly, and spring means biasing the forward end of the firing rod sidewardly to move the forward end away from said crucible opening subsequent to driving the firing .pin upwardly.

3. For use in combination with a welding crucible for molten metal, the crucible having a discharge opening at the lower end, a firing pin extending outwardly from the opening and drivable upwardly to free the opening for the discharge of molten metal, the crucible being mounted in a frame, a tripping mechanism comprising a mounting structure depending from the frame and having a ball-socket, a firing rod having a ball-shaped member intermediate its ends and received in said socket to permit both vertical and horizontal pivoting of the rod, means for positioning the forward end of the rod beneath the firing pin, guide means for directing said forward end upwardly to drive the firing pin upwardly and free said crucible opening, power means for driving the rearward portion of the firing rod downwardlyto move the forward portion upwardly, and biasing means for pivoting the firing rod sidewardly away from said crucible opening subsequent to driving the firing pin upwardly.

4. For use in combination with a welding crucible for molten metal, the crucible having a discharge opening at the lower end, a firing pin extending downwardly from the opening and drivable upwardly to free the opening for the discharge of molten metal, the crucible being mounted in a frame, a tripping mechanism comprising a firing rod pivotally mounted intermediate its ends, structure depending from the frame for positioning and guiding the forward end of the rod, said structure including a generally horizontal support surface for the rod and a generally vertical surface for positioning the forward end of the rod beneath the firing pin and directing the forward end upwardly to drive the firing pin upwardly and free said crucible opening, said generally vertical surface terminating at the point where the rod has struck the firing pin to permit sideward pivoting of the firing rod, biasing means for pivoting the firing rod sidewardly away from said crucible opening subsequent to driving the firing pin upwardly, and power means for driving the rearward portion of the firing rod downwardly to move the forward portion upwardly for striking the firing pin.

5. For use in combination with a welding crucible for molten metal, the crucible having a discharge opening at the lower end, a firing pin extending downwardly from the opening and drivable upwardly to free the opening for the discharge of molten metal, the crucible being mounted in a frame, a tripping mechanism comprising a firing rod pivotally mounted intermediate its ends, means for positioning the forward end of the rod beneath the firing pin, guide means for directing said forward end upwardly to drive the firing pin upwardly and free said crucible opening, biasing means for pivoting the firing rod sidewardly away from said crucible opening subsequent to driving the firing pin upwardly, and power means for driving the rearward portion of the firing rod downwardly to move the forward portion upwardly, said power means including plunger mounting structure on said frame over the rearward portion of the firing rod, a plunger slidably received in the plunger mounting structure and movable downwardly to drive the rearward portion of the firing rod downwardly, detent means on the plunger engageable with the plunger mounting structure for locking the plunger in an upper position, and spring means biasing the plunger downwardly when the plunger is locked in said upper position.

References Cited by the Examiner UNITED STATES PATENTS 293,468 2/1884 Jackson 222-509 460,575 10/1891 Grace 22-84 1,540,515 6/ 1925 Cuenot 22-79 J. SPENCER OVERHOLSER, Primary Examiner. R. D. BALDWIN, Assistant Examiner. 

1. FOR USE IN COMBINATION WITH A WELDING CRUCIBLE FOR MOLTEN METAL, THE CRUCIBLE HAVING A DISCHARGE OPENING AT THE LOWER END, A FIRING PIN EXTENDING DOWNWARDLY FROM THE OPENING AND DRIVABLE UPWARDLY TO FREE THE OPENING FOR THE DISCHAGE OF MOLTEN METAL, THE CRUCIBLE BEING MOUNTED IN A FRAME, A TRIPPING MECHANISM COMPRISING A FIRING ROD PIVOTALLY MOUNTED INTERMEDIATE ITS ENDS, MEANS FOR POSITIONING THE FORWARD END OF THE ROD BENEATH THE FIRING PIN, GUIDE MEANS FOR DIRECTING SAID FORWARD END UPWARDLY TO DRIVE THE FIRING PIN UPWARDLY AND FREE SAID CRUCIBLE OPENING, POWER MEANS FOR DRIVING THE REARWARD PORTION OF THE FIRING ROD DOWNWARDLY AND THE FOR- 